The invention herein pertains to power units employing gas turbines and designed particularly for use in driving land vehicles which have widely varying operating conditions such as occur when the vehicle is idling, accelerating, cruising, decelerating, carrying light, intermediate, and heavy loads, and traversing upwardly and downwardly inclined and level roads. During such operating conditions it is desirable to maintain as high efficiency of operation as possible.
Previous attempts to provide suitable power units for such purposes are exemplified by prior patents listed as follows.
These patents show various types of power units each employing one or more compressor and turbine stages and many types of gearing or other motion transmitting mechanisms for transferring power from the turbine or other power developing device to the wheels but none shows the structure disclosed in this application.
This invention relates generally to power systems and is more particularly directed to a power system designed specifically for use in a land vehicle and having a gas turbine as the main part with a turbosupercharged hot gas generating system as a secondary part to supply motivating fluid to the main part.
One of the objects of this invention is to provide a power unit having a main driving section and a secondary section for supplying the motivating fluid for the driving section, the secondary section having mechanism driven in part mechanically by the main driving section and in part by the energy remaining in the exhausted motivating fluid from the main driving section.
Another object of the invention is to provide the power unit mentioned in the preceding paragraph with elements to modify the motivating fluid at various stages of its preparation for the main driving section to improve the overall efficiency of the power unit as well as to reduce the output of noxious fluids during its operation,
A more specific object of the invention is to utilize a gas turbine as the main driving section in the power unit mentioned in the preceding paragraphs and a high pressure compressor as part of the secondary section, a differential gearing setup being employed to transmit power from the gas turbine to the high pressure compressor, the differential gearing setup including means for establishing predetermined gear ratios between the turbine and high pressure compressor at selected stages of operation of the power unit.
A further object of the invention is to provide a power unit of the type mentioned in the preceding objects in which the secondary section has a supercharger including a rotor with connected turbine wheel and compressor impeller parts, the latter supplying relatively low pressure air to the inlet of the high pressure compressor in response to the application of exhaust fluid from the gas turbine of the main driving section to the turbine wheel of the supercharger, the fluid exhausted from the turbine wheel of the supercharger being passed through a recuperator to utilize heat energy remaining in such fluid.
Still further objects reside in providing the secondary section of a power unit, such as mentioned above, with an intercooler between the supercharger and the high pressure compressor to reduce the initial heat of the pre-compressed air and premit a higher compression of the air with less effort in the high pressure compressor. Also in providing the compressors of the driving and secondary sections with rotary inlet guide vanes which can be controlled to permit such compressors to operate at higher speeds with reduced flows without surging in much the same fashion as conventional inlet guide vanes but with advantages in control simplicity and equipment cost.
It is an object also to provide the turbines of the driving and secondary sections with varible nozzles to control the power and speed of these turbines and consequently such characteristics of the power unit.
Other objects and advantages will be apparent from the following part of the description of one form of the invention selected for illustration in the accompanying drawings.